1. Field of the Invention
The present invention relates to wireless communication networks, and particularly to a method of assigning channels or bandwidth to multiple network users.
2. Discussion of the Known Art
Wireless communication networks having so-called multi-user detection or AMUD≅ capability, are generally known. In such networks, for example, two users may be assigned a common frequency channel on which to transmit voice, data or other information signals. Interference at a given receiver caused by the stronger one of the two user signals on the channel, can be canceled using known successive interference cancellation (SIC) or other techniques so that the data transmitted by the weaker user may also be detected and decoded. See, e.g, U.S. Pat. No. 6,404,760 (Jun. 11, 2002), which discloses a method of reducing multiple access interference in CDMA systems wherein a weighted replica of a strongest interfering signal is derived from the received signal, and then subtracted from a delayed version of the received signal. See also, U.S. Pat. No. 6,564,037 (May 13, 2003) which relates to multi-user detection in CDMA systems having beam forming receiving antenna arrays, and U.S. Pat. No. 7,158,804 (Jan. 2, 2007) which discloses scheduling of uplink signals from a number of mobile users based on certain metrics determined for each user. All relevant portions of the mentioned '760, '037 and '804 U.S. patents are incorporated by reference.
U.S. Pat. No. 7,072,315 (Jul. 4, 2006), also incorporated by reference, discloses a medium access control (MAC) protocol for assigning traffic channels to subscribers in an orthogonal frequency division multiple access (OFDMA) cellular network. In one example, a base station in the network broadcasts an omni-directional downlink sounding signal having a data sequence that is previously made known to the subscribers. Based on the condition of the sounding signal as received by an active subscriber, the subscriber transmits measured channel and noise-plus-interference information signals to the base station when paged by the base station, or when the subscriber has traffic (e.g., data packets) ready to transmit. The base station estimates broadband spatial processing gains across all available sub-channels, and determines optimal sets of non-overlapping traffic sub-channels for use by each active subscriber in order to avoid interference.